Metallic card clothing having thin points as well as method and apparatus for manufacturing such card clothing is illustrated in U.S. Pat. Nos. 4,233,711, 4,453,431 and 4,537,096. Card clothing capable of improved carding action has resulted from the practice of the inventions of the above patents wherein a sharpened leading edge is provided during the punching operation forming the teeth of the metallic wire clothing. It is desirable to produce card clothing having advantages provided by the inventions of the above patents and yet avoid the necessity for a special punching operation. U.S. Pat. No. 4,428,209 is illustrative of flexible clothing having wires with bent tips. Such wires are embedded in and project from the usual cloth backing. The bending of the teeth occurs prior to insertion of the teeth into the cloth backing. Such flexible clothing is distinguishable from the metallic wire clothing of the present invention wherein metal at the tips of the punched teeth is mechanically bent over, as by force exerted against the tips toward the base of the metallic wire with consequent bending over, prior to or after hardening to form sharp points extending generally in the direction of carding.
An object of the invention is to improve carding so as to produce a clearer web resulting in high quality yarn especially utilizing blends of cotton and synthetic fibers. Synthetic fibers such as polyesters of fine denier have proved to be especially difficult to card when blended with cotton making metallic card clothing with thin or sharp pointed teeth especially desirable.
It is an important object of the present invention to provide novel metallic wire card clothing having the advantages of thin points through a novel method and apparatus.
Another important object of the invention is the provision of a novel method of producing improved metallic card clothing by mechanical bending of metal at the tips of teeth punched in the wire clothing.
Another important object of the invention is the provision of improved card clothing having sharp points formed by mechanical bending of metal at the tips of the teeth with hardening of the teeth forming hardened metallic carding surfaces at the tips of the teeth.